Between 1847 and 1854 more than one million people left this European country and emigrated to the United States and elsewhere. What nationality were these people, and what natural event caused their mass emigration?

In the mid-19th century, a vast portion of Ireland's population, particularly poor tenant farmers, was almost entirely dependent on the potato for food. Beginning in 1845, a devastating blight, caused by a water mold called Phytophthora infestans, swept across the country. The disease destroyed the potato crop year after year, turning the vital food source into a black, inedible rot. This catastrophic crop failure led to widespread starvation and disease, a period known in Irish as An Gorta Mór, or The Great Hunger.

Faced with starvation and with limited aid, millions of Irish citizens saw emigration as their only chance for survival. The period from 1847 to 1854 marked the peak of this mass exodus. Over a million people boarded crowded and disease-ridden vessels, often called "coffin ships," to seek new lives abroad, primarily in the United States. The Great Famine tragically claimed about one million lives and forced another million to leave, permanently altering Ireland's demographic landscape and creating a vast Irish diaspora around the world.